I think I would politely ask the inspector how he came up with those numbers.
Unless he’s applying some derating or other correction factors, I just can’t figure it.
The only NEC 2008 change for fixed electric space heating equipment is 424.19, regarding disconnecting means being rated for 125% of the total load.
Again, this requirement is for the total load, not the branch circuit rating.
He may be taking the 3750-Watt heater load and dividing it by 125% to get his 3000-Watt limit. If so, that’s not the correct way to do it.
The branch circuits are considered continuous loads, so can only be loaded to 80%. Such as 20A X 240V X 80% = 3840W or 3328W if it’s 208V.
That would be a 16A load. 16A X 125% = 20A rated disconnecting means. Most DPST line-voltage thermostats have a 22 Amp load rating, so the 125% requirement for the disconnecting means is already met.
Other than that, I’m at a loss to explain.
